Fix various problems with matching out-of-line definitions of static

Fix various problems with matching out-of-line definitions of static
class members to the corresponding in-class declaration.

Diagnose the erroneous use of 'static' on out-of-line definitions of
class members.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@66740 91177308-0d34-0410-b5e6-96231b3b80d8